If it's a block of cheddar and not too moldy I'll cut the mold off and eat eat. Other than that with any other cheeses I throw it away When is cheese expired? This question is a controversial topic in the food world. Some people say they scrape the mold off cheese and eat it, while others won't touch it past the expiration date. We consulted an expert to find out how long cheese is safe to eat. Kantha Shelke, a food scientist for Corvus Blue LLC and spokeswoman for the Institute of Food Technologists, pointed out the specifics to Business Insider. Given the apparent dangers of eating certain molds, it's important to know what to use, what to toss, and what to cut off and use. http://finance.yahoo.com/news/definitively-solved-debate-over-whether-171430567.html
Some types of mold are used to make cheeses, such as Brie and Camembert. Blue cheese is moldy cheese with penicillum mold. These molds are safe to eat. Soft or crumbly cheeses that turn moldy with age should be discarded because the mold can get all through them and it is not safe. However hard cheese doesn't get penetrated by mold, it is essentially on the surface. If a block of cheddar get some mold spots, I just trim them off and the rest of the cheese is fine.
You have to be careful because listeria is a pretty nasty bacteria that grows at cold temps. But I still just cut off the mold.
I'm picky too. I won't touch anything past the expiration date no matter how good it looks. A friend of mine ate some cabbage for slaw three days past the expiration date on the package and he had a "loose" relationship with his toilet for 48 hours.